The collection, preservation, and processing of biological samples for DNA testing often requires a number of devices that could introduce DNA contamination and sample mix-up as transfers are made. Biological samples, such as those for forensic DNA analysis, are usually collected from blood, saliva, semen, and other bodily fluids by wiping onto a cotton-tipped swab or a cotton pad. The swabs, pads, or other collection devices are placed into plastic or paper containers or bags for storage, preservation and future analysis. Wet samples could be prone to microbial action and biological degradation if not dried or preserved properly. Cotton swabs or cotton pads may obtain small samples with a limited amount of biological materials which can be contaminated or diminished when the swab or pad comes in contact with the container or bag, or when the swab or pad is transferred to a processing or testing container.
The biological samples are then transferred to microtiter plates or tubes like microfuge tubes for testing or processing. Microfuge tubes are small plastic tubes capable of holding between 0.4-2.0 ml of liquid and are constructed to be placed into racks for automated manipulation and withstand the forces exerted by a centrifuge during centrifugation. Biological samples that may have dried in the previous container may be removed from the previous container, inserted into the microfuge tubes, and combined with a solution to separate DNA, for instance. The microfuge tubes usually have caps sized and shaped to protect and cover the tube opening, while maintaining the inside of the tube in an aseptic condition. The caps are usually attached by a flexible hinge and are closed and secured by press fit. Closing the cap often causes an annular sealing portion of the underside of the cap to be pushed downward into the tube. The caps are secured against accidental opening by a number of means which vary in effectiveness, including friction, integrated lid catches, or separate lid clamps. The caps are often provided with an unsealing portion opposite the cap hinge extending horizontally beyond the outer diameter of the tube's cap flange to provide a standard lifting tab. A thumb, thumbnail, or opener device may be used to lift upward on the lifting tab, but may lead to contamination of the sample held within the microfuge tube. Even the use of surgical gloves may not prevent cross-contamination between successively opened microfuge tubes. Container opener tools may reduce incidence of contamination however may not preclude contamination.
Biological samples that are not immediately processed and tested may be stored in the collection container for indefinite periods of time, in which case, the biological samples will benefit from drying or other preservation techniques to prevent degradation of the sample. Traditionally sample drying has been allowed to occur naturally, or aided by the use of protected holes in the cap of a container whereby air is allowed to circulate while limiting potential contact between the sample and contaminants. Drying or preservation agents, such as desiccants, may be used. However drying or preservation agents present contamination problems where the agent is placed in the same container as the biological sample.
There is a need for a container which may serve as the collection, processing, and testing container for biological samples, preventing the possibility of contamination of samples through transfer between containers. Further, there is a need for a container which aids in drying and preservation of biological samples without the potential contamination effects of exposing the biological sample to outside airflow or contamination by contact with a drying or preservation agent.